Lee,
Sure! Pull the board and install a bridge rectifier. AC leads go the the center rail pickup, the other to the frame. + and - go to the motor leads. Direction of travel depends on the position of the motor leads. Reverse them if you want to go the other way. For a solution that restores direction switching capability, go to Dallee Electronics . They are not that expensive.
Also, it MAY be possible to repair the board. Those boards had individual components soldered to them. If you know which are dead, they can be pulled and replaced.
Chris
LVHR